1. Field of the Invention
The present invention is directed to a work vehicle having an operator""s seat with two working positions for controlling two work implements, wherein the position of the operator""s seat controls the application of a hydraulic pump to the second work implement.
2. Description of the Prior Art
Backhoe loaders are a common type of work vehicle for performing two work operations. The backhoe loader is provided with a front mounted loader and a rear mounted backhoe. The operator""s cab is provided with a reversible seat which faces forward for transport and loading operations and to the rear for backhoe operations.
The backhoe functions of the backhoe has a higher fluid demand than the loader functions of the loader. To provide sufficient fluid, a second fluid gear pump has been provided supplying additional pressurized hydraulic fluid to the backhoe control valves. In current production machines, a first hydraulic gear pump supplies pressurized hydraulic fluid to the loader control valves, the stabilizer control valves and the backhoe control valves in series through a first supply line. A second supply line directs pressurized hydraulic fluid from the second hydraulic gear pump to the first supply line upstream from the backhoe control valves and downstream from the stabilizer control valves.
Other backhoe loader manufacturers have used manually operated switches to decouple one of the pumps from the hydraulic circuit.
It is an object of the present invention to provide a simple and automatic mechanism for coupling and decoupling a second hydraulic pump to the operation of a second work implement.
A backhoe loader is provided with a front mounted loader and a rear mounted backhoe. The operator""s cab of the backhoe loader is provided with a reversible operator""s seat having a first working position facing the loader and a second working position facing the backhoe. A first hydraulic pump directs pressurized hydraulic fluid through a first supply line to backhoe control valves, stabilizer control valves and loader control valves that are mounted in series. A second hydraulic pump directs pressurized hydraulic fluid through a second supply line to the first supply line upstream from the loader control valves. The second supply line is provided with a two-position solenoid valve. In its first position the valve directs the pressurized hydraulic fluid from the second hydraulic pump to sump. In its second position the valve directs pressurized hydraulic fluid from the second hydraulic pump to the first supply line. The solenoid of the two-position solenoid valve is in electrical communication with a detector. The detector sends a first signal if the operator""s seat is in its first working position and a second signal if the operator""s seat is in its second working position. The detector is a conventional seat switch currently used on production backhoe loaders for different applications.